JPH0698406B2 - Screw rotor manufacturing method - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a screw rotor having helical teeth, which is used in screw compressors, screw pumps and the like.

(Prior Art) As a means for efficiently producing a screw rotor by plastic working, a method disclosed in JP-A-50-156013 is conventionally known. As shown in FIG. 12, the method is to produce a material W ₁ having linear teeth 11A extending from a base 10A, and twisting the material W ₁ to produce a screw rotor.
As another method, as shown in JP-A-62-63190, a die is provided with a toothed groove having a helix angle and a core die, and a raw material is extruded from the die to form a torsion tooth and a core in one process. A method of forming a screw rotor having holes is known.

(Problems to be Solved by the Invention) In screw compressors, pumps, etc., the twist angle of the helical teeth is determined by the required performance such as the compression ratio, and may require a twist angle of 40 ° inside and outside, for example. .

However, if the former of the above-mentioned prior art, a method of twisting a material having a straight tooth, is used to process a helix angle of 40 °, the amount of machining is large and a uniform helix angle can be obtained over the entire length of the tooth. It may not be possible or the twist angle of each tooth may not be uniform.

Further, in the latter method of molding with a die in which the tooth profile groove has a helix angle, since the helix angle is large, resistance to extrusion in the tooth profile groove is large, and a female rotor having a thin tooth profile may not have a tooth profile. Yes, the mold wears too much.

Therefore, it is an object of the present invention to overcome these drawbacks of the prior art and to obtain a means for easily manufacturing a rotor having a core hole and having high accuracy.

(Means for Solving the Problems) One of the means for solving the problems of the present invention is to provide a central hole, a plurality of tooth-shaped grooves extending radially from the central hole and having a gentle helix angle, and holding the toothed groove in the central hole. The step of extruding a toothed material having a core hole and twisted teeth with a gentle helix angle from a die including a core die, and inserting a core metal into the core hole of the toothed material to form the toothed material. It is characterized by comprising a step of twisting cold or hot.

In addition, another one of the solving means is a die including a center hole and a plurality of tooth-shaped grooves extending radially from the center hole and having a gentle helix angle, and a toothed member having a helix tooth with a gentle helix angle. A step of extruding a material, a step of forming a core hole in the toothed material, and a step of inserting a core metal into the core hole of the toothed material and applying a twist to the toothed material cold or hot It is characterized by consisting of.

(Operation) In one of the above means, a toothed material having a gently twisted tooth and a core hole is extruded, and in the next step, a core metal is used to prevent deformation of the core hole portion and Torsional force is applied to impart a helix angle to the final helix angle of the rotor.

Further, in the other one of the above-mentioned means, a toothed material having a gentle helical tooth is formed, then a core hole is bored, a cored bar is inserted into the core hole, a twisting force is applied, and a final twist angle is obtained. Is given.

(Examples) Examples will be described below with reference to the drawings. In FIG. 1, reference numeral 1 denotes a die for the first step of the female rotor, which is a combination of a male die 2 and a female die 3. At the center of the male die 2, a mandrel 4 is continuously provided with four arms 5, and the passages 6, 6 ... Between the arms are communicated with a confluence chamber 7.
Has a little protruding from the end of the confluence chamber 7. on the other hand,
The female die 3 has a central hole 8 and a radial tooth groove 9 following the central hole 8.
The mandrel 4 is inserted into the center hole 8 on the side of the base end face 3a. As shown in FIGS. 1 and 2, the female die 3 is provided with five tooth-shaped grooves 9 extending radially from the central hole 8 and having a helix angle of, for example, 20 ° with respect to the longitudinal direction. There is a phase difference e between the inlet side indicated by the dotted line, the solid line outlet side, and the solid line outlet side.

When this is used, as shown in FIG. 3, a helical tooth 11B having a helix angle of α ₁ = 20 ° extending from the base 10B and a core hole at the center.
The toothed material W ₂ on which 12B is formed is formed.

When a billet made of highly heated aluminum alloy is pushed into the die 1 shown in FIG. 1, the arms 5, 5 of the male die 2 pass through the passages 6, 6 ... 7, where they are welded and integrated again to be pushed into the female die 3. By configuring the male die 2 with such a structure, the mandrel 4 can be shortened and the core hole is not displaced due to the runout. Also, if the mandrel is attached to a long container and the female die 3 is connected without using such a male die 2, a large resistance is generated against the billet at the base end face 3a thereof. Can be extruded with low resistance.

Toothed materials W ₂ made in the first step of above, the following second
Torsion is added in the process. In this second step, the toothed material is cold worked or hot worked at 200-250 ° C. Insert the metal core 13 into the core hole of the material W ₂ as shown in FIG. 4 and hold it by the urethane rubber holders 14a and 15a of the fixed chuck 14 and the roll chuck 15, and hold the roll chuck 15 in the direction of arrow 16. Twisting to form a toothed material W ₃ having twisted teeth 11 having a twist of, for example, α ₂ = 40 ° on the teeth extending from the base 10 and having a core hole 12 in the base 10.

By inserting the core metal 13, it is possible to
The deformation of the core 10 and the core hole 12 is prevented, and therefore the deformation of the teeth 11 due to the deformation is also prevented. The accuracy of the teeth 11 is generally higher when the clearance C between the core hole 12 and the core metal 13 is smaller, and the clearance C is changed by the core metal having a different diameter for the female rotor made of an aluminum alloy, and the two adjacent pieces after the twisting process. When the lead difference between the teeth 11a and 11b of the tooth was calculated, the curve LD of FIG. 10 was obtained. If the clearance C is small, the lead difference is small and the accuracy is improved. However, if the clearance C is too small, the core metal 13 is locked in the core hole 12 in the lock region K.

In this way, by inserting the core metal 13 and twisting it, a rotor material W ₃ with good accuracy can be obtained, but this toothed material W ₃ is twisted due to uneven temperature distribution during heating. Since an angular error is unavoidable and distortion occurs in the chuck portion, if necessary, a shaping process of the third step or later is performed to correct this. The shaping die 17 used in the third step is shown in FIG. 5, and the tooth space 18 has a helix angle of about twice that of the female die 3 in FIG. The phase difference is 2e.

When the shaping die 17 is fixed, the toothed material W ₃ obtained in the second step is pushed in, the tip is grasped by the chuck, and the twisting angle is pulled out to correct the variation in the twist angle. The female rotor W ₄ shown in FIG.

7 and 8 each show a male rotor which meshes with the female rotor W ₄ and which has four round teeth. The male rotor W ₅ shown in FIG. 7 has round teeth 19, 19 ... And a core hole 20 each having a substantially semi-circular shape, and a female die having a tooth groove corresponding to the round teeth, a chuck, and a shaping die are used. It is processed in the same procedure as the first, second and third steps.

The male rotor W ₆ shown in FIG. 8 has a substantially semicircular and hollow torsion tooth 21.
In order to mold this male rotor W ₆ , a long container and a mandrel are used in place of the male die 2 in the first step, and 4 pieces are provided around the mandrel. The mold is prepared, and a semi-molten material or a billet heated to a high temperature is pushed in for molding, and the second and third steps are performed by the same means as described above.

The female rotor W ₄ and the male rotor W ₅ or W ₆ thus formed are
The shafts are inserted and fixed in the core holes 12 and 20, and in order to prevent friction and noise from being generated on the rotor meshing surfaces, the interlocking operation is performed to rotate the male and female rotors while maintaining a slight gap. A gear is fixed to the shaft.

However, it is difficult to achieve an accuracy with a constant gap over the entire helical tooth, and partial contact may occur during operation. In order to reduce friction and noise generated in this case, at least one of the rotors is coated with an anti-friction resin layer as a fourth step. Figure 9 shows female rotor
An example in which an anti-friction resin layer 23 is formed on W ₄ is shown, and the resin layer 23 has a base such as polyimide, polyamide, polyamide-imide, epoxy, polyvinyl chloride, or silicone.
Synthetic resins such as epoxy, silicone urethane, silicone polyester are used.
_{S 2, WS 2, BN,} (CF) n, Sn powder was added PTFE or the like, and a film thickness of 10~1500μm by composite coating. This film improves the sliding property of preventing the metals from coming into contact with each other.

If the gap between the male and female rotors after coating the anti-friction resin layer is not appropriate and uniform, the surface layer of the anti-friction resin layer should be cut with a hob or removed by grinding with a grindstone to correct it in the fifth step. A highly accurate screw rotor having wear resistance can be obtained.

Next, another manufacturing method will be described with reference to FIG. In the figure, 25 is a die, which is composed of a male die 26 and a female die 27. Unlike the die 1 of FIG. 1, this die 25 has no mandrel, and the male die 26 has only a passage 28 and a confluence chamber 29. And the female die 27 has the same structure as in FIG.

Therefore, when the billet is pushed into the nozzle 15, the female die is
A toothed material having no core hole is extruded from 27, and the core hole is formed in the material by using a drill or the like. After the core hole is drilled, a core metal is inserted in the same manner as the toothed material made by the die 1 and twisted. When using this die 25, the extrusion pressure is low.

(Effects of the Invention) As described above, according to the means of claim 1, since the toothed material having the core hole and the helical teeth with the gentle spiral angle is extruded in the first step, the step of boring the core hole can be omitted. Along with this, it is possible to pre-process torsion teeth. Then, in the next processing, the core metal is inserted into the core hole and the remaining twist angle is added, so the core metal prevents unauthorized deformation of the material, and the twist angle is small in this processing, so it is reasonable and accurate. Processing is done,
There is an effect that a product with accuracy that does not require cutting finish can be obtained.

According to the second aspect of the present invention, the helical teeth are pre-processed in the first step, but since the core hole is not formed, a core hole punching step is required, but the pushing force is small. Then, by inserting the core metal and adding a twist, a product with high accuracy can be obtained as in the case of the first aspect.

[Brief description of drawings]

1 (a) and 1 (b) are a rear view and a vertical sectional view of a die used in the first step of the present invention, FIG. 2 is a front view of a female die, and FIG. 3 is a toothed material after the first step. Front view, Figure 4 is second
Fig. 5 is an explanatory view of the process, Fig. 5 is a front view of a shaping die for the third process, Figs. 6 (a) and (b) are front views and sectional views of a female rotor, and Figs. 7 (a) and (b) are male. 8A and 8B are front views and cross-sectional views of another male rotor, and FIG. 9 is a cross-sectional view of a rotor coated with a resin layer.
FIG. 11 is a diagram showing product accuracy, FIG. 11 is a longitudinal sectional view of a die used for carrying out another manufacturing method, and FIG. 12 is a perspective view of a toothed material processed by a conventional method. 1, 25 …… Dies 2, 26 …… Male dies 3, 3A, 3B, 27 …… Female dies 9, 9A, 9B …… Tooth groove 17 …… Shaping dies W ₁ , W ₂ , W ₃ …… With teeth Material W ₄ , W ₅ , W ₆ ... Rotor

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masami Hoshi, Inventor Masami Hoshi, 1-4-1 Chuo, Wako, Saitama Prefectural Technology Research Institute, Honda R & D Co., Ltd. Takaji Hibino (56) References JP 62-63190 A) JP-A-50-156013 (JP, A) JP-A-57-97816 (JP, A) JP-A-61-259838 (JP, A) JP-A-58-196124 (JP, A) JP-A-2 -37194 (JP, A)

Claims (2)

[Claims] 1. A die having a center hole, a plurality of tooth-shaped grooves extending radially from the center hole and having a gentle helix angle, and a core die held in the center hole, wherein a core hole and a gentle helix angle are formed. Characterized by comprising a step of extruding a toothed material having a helical tooth, and a step of inserting a core metal into a core hole of the toothed material and applying a twist to the toothed material cold or hot. Screw rotor manufacturing method. 2. A step of extruding a toothed material having helical teeth with a gentle helix angle from a die having a central hole and a plurality of tooth-shaped grooves extending radially from the central hole and having a gentle helix angle. And a step of forming a core hole in the toothed material, and a step of inserting a core metal into the core hole of the toothed material and applying a cold or hot twist to the toothed material. Screw rotor manufacturing method.